1. Field of the Invention
The present invention relates to a socket for an electric component, which is adapted for detachably accommodating an electric component such as an IC package or the like to connect the same to a circuit board, e.g., a printed circuit board, and more particularly to a socket for an electric component, which is provided with a plurality of contact pins arranged in a socket main body and a slide plate for permitting each of the plurality of contact pins to be brought into contact with or separated apart from each of connection terminals of the electric component through displacement of the contact pins, and is capable of reducing an amount of deformation of the slide plate for equalizing the amount of movement of the slide plate.
2. Description of the Related Art
Conventionally, this type of the socket for an electric component, in particular, an open-top-type socket includes therein, as shown in FIG. 11, a socket main body 1 having an accommodating portion for accommodating an electric component, a plurality of contact pins (not seen in FIG. 11 because disposed inside the socket main body 1) which are mounted in the socket main body 1 and connectable to/separable from connection terminals of the electric component, a socket cover 2 mounted on the top of the socket main body 1 movably in a vertical direction, a slide plate (not seen in FIG. 11 because disposed inside the socket main body 1) which is vertically movably disposed within the socket main body 1 so as to displace the contact pins, so that the contact pins come in contact with/disconnect from the connection terminals of the electric component, and drive levers 3, 4 which are provided between the socket main body 1 and the bottom face of the socket cover 2 to press both end portions of two opposing sides of the slide plate when the socket cover 2 is lowered, thereby lowering the slide plate. In the meantime, the drive levers 3, 4 are provided in a pair on each of the opposing two sides of the socket main body 1, whereby two pairs of the levers are provided.
The IC package as an electric component has a number of solder balls projecting from the bottom face of the package main body to be used as connection terminals such that the solder balls are arranged in a matrix configuration In a vertical direction and a transversal direction. The slide plate is formed into, for example, a rectangular shape in its plan view and a contact pin is inserted into each of a number of pin holes bored in a substantially entire surface excluding the peripheral region and then, when this slide plate is moved vertically, i.e., up and down, each contact pin is urged to do displacement from its original position.
When the IC package is accommodated in the socket main body 1 and connected to the socket for an electric component, the socket cover 2 mounted on the top of the socket main body 1 is vertically moved to rotate the drive levers 3, 4 pivoted on the inner wall portion of the socket main body 1. Pressing portions 3a, 4a provided on the intermediate portion of the drive levers 3, 4 press the slide plate to move the slide plate vertically, so that the contact pins are urged to make displacement by the vertical motion of the slide plate in order to resultantly open/close the contact portion at the tip end of each contact pin thereby bringing it into contact with the connection terminal of the electric component (see, for example, Japanese Laid-open (Kokai) Patent Application Publication No. 2002-8809).
However, because in the conventional socket for an electric component, as shown in FIG. 12, the slide plate 5 that is rectangular in its plan view is lowered by pressing both end portions 6a, 6b; 7a, 7b of opposing two sides 6, 7 thereof, the descent amount of, particularly, a central portion of other opposing two sides 8, 9 not pressed directly by the drive levers 3, 4 must be relatively small, so that the slide plate 5 is often deformed in a curved manner with that portion having the form of a ridge. This is because the slide plate 5 receives a resistance against the descent thereof, due to sliding contact of the number of contact pins inserted in substantially the entire surface of the slide plate 5 with the same slide plate 5.
If the slide plate 5 is deformed in this way, the moving distance thereof in the vertical direction becomes unequal between the opposing two sides 6, 7 and the central portion therebetween, so that the contact portions at the tip ends of the contact pins disposed at the central portion of the slide plate 5 fail to be sufficiently opened, thereby often causing a contact failure between the contact pin and the connection terminal of the electric component. In addition, in recent years, the IC package is highly integrated and as the number of the connection terminals on the bottom face of the package main body has been increased, the number of the contact pins is also increased, thereby presenting multiple pin configuration trend. In this case, as the contact pins are formed into the multiple pin configuration, the resistance against the above-mentioned descent due to sliding contact of the slide plate 5 with the contact pins is increased so as to increase the deformation of the slide plate 5 and therefore, a contact failure occurs between the contact pin and the connection terminal of the electric component. Accordingly, the conventional socket for an electric component cannot often cope with the multiple pin configuration trend of the contact pin.